Corticobulbar tract. And that includes these upper motor neuron axons that are going to innervate lower motor neurons in the brain stem and because the wiring is a little bit more complicated in the brain stem, we can get some different patterns of weakness with abnormalities of this pathway.
Activity theory (AT; Russian: ÑÐµÐ¾ÑÐ¸Ñ Ð´ÐµÑÑÐµÐ»ÑÐ½Ð¾ÑÑÐ¸) is an umbrella term for a line of eclectic social sciences theories and research with its roots in the Soviet psychological activity theory pioneered by Lev Vygotsky, Alexei Leont'ev and Sergei Rubinstein.
A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment.Such fact-supported theories are not guesses but reliable accounts of the real world. theory can be normative (or prescriptive), meaning a postulation about what ought to be. It provides goals, norms, and standards. A theory can be a body of knowledge, which may or may not be associated with particular explanatory models.